Screw shaft element



FIG. 1 is a perspective view of a screw shaft element showing a first embodiment of our new design;

FIG. 2 is a front view of the design of the first embodiment;

FIG. 3 is a back view of the design of the first embodiment;

FIG. 4 is a left view of the design of the first embodiment;

FIG. 5 is a right view of the design of the first embodiment;

FIG. 6 is a top view of the design of the first embodiment;

FIG. 7 is a bottom view of the design of the first embodiment;

FIG. 8 is a perspective view of a screw shaft element showing a second embodiment of our new design;

FIG. 9 is a front view of the design of the second embodiment;

FIG. 10 is a back view of the design of the second embodiment;

FIG. 11 is a left view of the design of the second embodiment;

FIG. 12 is a right view of the design of the second embodiment;

FIG. 13 is a top view of the design of the second embodiment; and,

FIG. 14 is a bottom view of the design of the second embodiment.

The broken lines in the drawings illustrate portions of the screw shaft element and form no part of the claimed design. 

CLAIM The ornamental design for a screw shaft element, as shown and described. 